Fan shroud of a motor vehicle

ABSTRACT

This disclosure relates to a fan shroud of a motor vehicle, having a shroud body which comprises a round airflow opening for a fan impeller. The fan shroud additionally includes a motor mount which is arranged above the airflow opening and is attached by means of a strut to a fastening dome. The fastening dome is attached to the shroud body and is oriented perpendicularly to said shroud body. The radially outer end of the fastening dome, with reference to the airflow opening, is at a varying distance from the mid-point of the airflow opening. This disclosure additionally relates to a cooler fan of a motor vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German patent application Serial No.DE 10 2018 214 782.5 filed Aug. 30, 2018, the disclosure of which ishereby incorporated in its entirety by reference herein.

TECHNICAL FIELD

This disclosure relates to a fan shroud of a motor vehicle whichcomprises a shroud body. The disclosure additionally relates to a coolerfan of a motor vehicle. The cooler fan is expediently a main fan.

BACKGROUND

Motor vehicles with an internal combustion engine comprise aconsiderable build-up of heat during operation. A liquid coolant, which,in turn, has to be cooled, is usually used to maintain the operatingtemperature of the internal combustion engine and also for the operationof an air conditioning system. This usually takes place by means of acooler network which is acted upon by a driving wind and exchanges heatwith the coolant. For example, the coolant is conducted in pipes whichare worked into the cooler network. As, in particular at low vehiclespeeds, the driving wind is normally insufficient for cooling purposes,it is known to use an electric fan by means of which the driving wind isstrengthened.

In this connection, the fan is arranged downstream of the cooler networkin the direction of travel. With the assistance of a fan impeller of thefan, the air is sucked through the cooler network and conducted to theinternal combustion engine. There the air absorbs the excessive heat ofthe internal combustion engine and removes it. In this connection, theair contacts the internal combustion engine in a substantially obtusemanner and is deflected by said internal combustion engine, for exampleby 90°. As a result, turbulence occurs which results in an increase inflow resistance and consequently in a decrease in efficiency. Noise isalso generated which is perhaps disruptive.

SUMMARY

The object underlying this disclosure is to provide a particularlysuitable fan shroud for a motor vehicle and a particularly suitablecooler fan for a motor vehicle, flow resistance being reduced inparticular.

With regard to the fan shroud, said object is achieved according to thisdisclosure by the features of claim 1 and with regard to the cooler fanby the features of claim 11. Advantageous further developments anddesigns are the object of the respective dependent claims.

The fan shroud is a component part of a motor vehicle and, inparticular, a component part of a cooler fan. In this connection, thefan shroud is suitable, in particular is provided and designed to bemounted on a cooler. For example, the cooler is covered at least inpart, conveniently substantially completely by means of the fan shroud,in particular at least parts of the fan shroud abutting against thecooler or being at a spacing from said cooler. The cooler fan andconsequently also the fan shroud preferably serve for cooling aninternal combustion engine of the motor vehicle. In a convenient manner,a coolant is cooled by means of the cooler, and/or an airflow isconducted to the possible internal combustion engine by means of the fanshroud. The motor vehicle is conveniently land-based and is, forexample, a passenger vehicle. As an alternative to this, the motorvehicle is a commercial vehicle, for example a truck or a bus.

The fan shroud includes a shroud body which is preferably designed in asubstantially flat manner. Conveniently, the shroud body, in thisconnection, comprises an enlarged extent, for example by more than tentimes, in two dimensions compared to the dimension extendingsubstantially perpendicularly hereto. The dimensions of the shroud bodyare preferably between 1 m×0.5 m and 0.8 m×0.5 m. For example, the edgesof the shroud body are curved so that the shroud body is designed in asubstantially shell-like manner.

The shroud body comprises a round airflow opening (air passage, recess).In the mounted state, a fan impeller is arranged inside the airflowopening. In particular, the airflow opening comprises edge-side contoursin which corresponding contours of the fan impeller engage in themounted state. Consequently, leakage air is reduced. The diameter of theairflow opening is conveniently between 0.2 m and 0.6 m. In other words,the fan impeller preferably comprises a diameter which is between 0.2 mand 0.6 m. The fan impeller is expediently arranged in the mounted statesubstantially parallel to the shroud body and preferably comprisessubstantially the dimensions of the airflow opening. The fan impeller isrotated, in particular, in a certain direction of rotation duringoperation. The shroud body is preferably provided and designed in asuitable manner for this purpose.

In addition, the fan shroud includes a motor mount. The motor mount issuitable, in particular is provided and designed to hold an electricmotor. In other words, an electric motor is mounted on the mount in themounted state. The electric motor is, for example, a brush commutatormotor. In a particularly preferred manner, however, the electric motoris a brushless direct current motor (BLDC). The fan impeller is drivenby means of the electric motor in the mounted state. Consequently, theaxis of rotation of the electric motor is perpendicular to the shroudbody and in a convenient manner extends in an axial direction withreference to the airflow opening through the mid-point thereof, that isto say perpendicularly to the extent of the airflow opening.

The motor mount is arranged above the airflow opening. In other words,the motor mount is axially offset with reference to the airflow opening,that is to say perpendicular to the extent of the airflow opening and/orof the shroud body. In the case of a projection of the motor mount tothe airflow opening perpendicularly to the extent of the shroud bodyand/or perpendicularly to the airflow opening, the airflow opening iscovered at least partially, preferably fully, by means of the motormount. In a convenient manner, the projection of the motor mount isarranged, in this connection, substantially centrally in the airflowopening.

In addition, the fan shroud includes a strut which is attached to afastening dome. The strut itself is attached to the motor mount, forexample is integrally formed. Consequently, the motor mount is attachedto the fastening dome by means of the strut. The fastening dome isattached, preferably fastened, to the shroud body.

Consequently, the motor mount is attached to the shroud body by means ofthe strut and the fastening dome and is stabilized in this way. Thefastening dome is oriented at least partially perpendicularly to theshroud body and consequently comprises an axial progression. In aconvenient manner, the fastening dome is oriented fully perpendicularlyto the shroud body. In other words, the fastening dome is perpendicularto the airflow opening.

In particular, the spacing between the motor mount and the airflowopening is realized by means of the fastening dome. In a convenientmanner, the fastening dome is situated on the same side of the shroudbody as the motor mount and the strut, which simplifies construction.The fastening dome comprises a radially outer end with reference to theairflow opening, that is to say in particular with reference to themid-point of the airflow opening. In this connection, the distancebetween the radially outer end and the mid-point varies, in particularin the tangential direction with reference to the airflow opening. Inother words, the radially outer end of the fastening dome does notdescribe a circle, the mid-point of which coincides with the mid-pointof the airflow opening. Consequently, the distance of the outer end isnot constant, and the radially outer boundary of the fastening dome isnot delimited by means of a circle-segment-like or cylinder-segment-likesurface, the mid-point of which coincides with the mid-point of theairflow opening.

In a convenient manner, the motor mount and/or the fastening dome is/arearranged in the mounted state downstream of the shroud body withreference to the direction of the airflow. In the mounted state, airflows through the airflow opening in particular when the vehicle ismoved and/or the fan impeller is driven.

On account of the varying distance of the outer end, it is possible, bymeans of the fastening dome, to form the air stream passing through theairflow opening during operation and to control it in a suitable manner.In particular, a radial component is introduced into the airstream inthis connection at least in part by means of the fastening dome. Thefastening dome is suitable, in particular provided and set up for thispurpose, and is consequently suitably designed. As a result of this, theair stream, which passes through the airflow opening, does not contact apossible object arranged downstream of it in a simply oblique manner.Consequently, less turbulence is created in the air stream, and, inaddition, stall of an air stream is prevented by means of the fasteningdome. As a result, a spread of turbulence is reduced so that the flowresistance is reduced.

For example, the fastening dome, the shroud body, the motor mount and/orthe struts are each separate components. In a particularly preferredmanner, however, the components are integrally formed together. In otherwords, the fan shroud is expediently created in one piece. The fanshroud is preferably created in one piece from a plastics material. In apreferred manner, the individual components, that is to say the shroudbody, the motor mount, the strut and the fastening dome are cast. Thecomplete fan shroud is preferably created using a plastics materialinjection molding process. Mounting is simplified and mechanicalintegrity increased in this way.

For example, the shroud body includes a dynamic pressure control valve.This comprises a valve which is pivotably arranged within an opening inthe shroud. In the case of comparatively high dynamic (air) pressure,the valve is opened so that an additional passage of air through theshroud body is made possible independently of the airflow opening.Consequently, a comparatively large air throughput through the shroudbody is also possible in the case of a comparatively strong air streamwhich contacts the shroud body, as is the case, in particular, when themotor vehicle is moving at a comparatively high speed. In this case, theairflow opening is open when the motor vehicle is at a standstill, whichincreases efficiency.

For example, the fastening dome comprises a substantially constant crosssection over its progression in the axial direction perpendicularly tothe extent thereof, that is to say parallel to the shroud body and/orthe airflow opening. In a particularly preferred manner, however, thecross section is modified along the progression thereof, the crosssection surface decreasing expediently as the distance to the shroudbody increases. In this connection, the cross section is modified, forexample, or in a particularly preferred manner is similar but simplymade smaller. On account of the consequently tapering cross section, inparticular of the scaling, improved conducting of the air stream is madepossible so that the air stream is prevented from stalling even where anaxial end of the fastening dome is at a spacing from the shroud body.For example, reinforcing ribs, which extend, for example, radiallyand/or tangentially, are attached to the fastening dome on the radiallyouter end thereof. In a preferred manner, the reinforcing ribs compriseat least one at least radial component. The reinforcing ribs areconveniently designed in a platelet shape. The position of the fasteningdome is stabilized by means of the reinforcing ribs, which increasesrobustness.

For example, the maximum extent of the fastening dome perpendicular tothe extent thereof, that is to say parallel to the shroud body and/orthe airflow opening, is between 0.1 m and 0.01 m. Consequently, acomparatively compact fastening dome is realized. As an alternative tothis or in combination with it, the maximum extent of the fastening domealong the extent thereof, that is to say perpendicular to the shroudbody and/or the airflow opening, is between 0.03 m and 0.2 m. Thefastening dome comprises expediently, with reference to the airflowopening, a progression at least partially in the tangential direction.In particular, the extent in the tangential direction is between 10% and60% of the extent of the fastening dome in the axial direction, that isto say perpendicular to the airflow opening. Consequently, the fasteningdome is comparatively robust.

For example, in addition, the distance between the radially inner end ofthe fastening dome, determined with reference to the airflow opening,and the mid-point of the airflow opening varies. In a particularlypreferred manner, however, the distance between the radially inner endof the fastening dome and the mid-point of the airflow opening isconstant. In other words, the radially inner end of the fastening domeis formed corresponding to a circle segment or cylinder segment. In thisway, the air stream passing through the airflow opening in asubstantially straight-lined manner is swirled comparatively little. Inparticular, in this connection, the wall of the fastening dome situatedon said side is designed to be comparatively smooth so that turbulenceformation is further reduced. The radius of the airflow opening ispreferably the distance between the radially inner end to the mid-pointso that the fastening dome is aligned with the airflow opening. As aresult, it is situated comparatively close to the motor mount, which iswhy the installation size of the shroud body is reduced. The stabilityof the motor mount is also increased. In addition, the radially innerend of the fastening dome causes the air stream passing through theairflow opening to be conducted in a substantially straight-linedmanner, which further increases the efficiency. On account of theconstant distance, the cross section of the fastening dome parallel tothe airflow opening is consequently not symmetrical with reference to atangential straight. In an alternative to this, the cross section is,for example, symmetrical, and the distance between the radially innerend and the mid-point is consequently not constant.

The fastening dome preferably includes a thickening which extendsconveniently in the radial direction with reference to the airflowopening. The thickening is situated, for example, between the twotangential ends of the fastening dome with reference to the airflowopening. For example, the fastening dome comprises a circle segment ascross section perpendicular to the airflow opening, the mid-point of thecircle being displaced from the mid-point of the airflow opening in thedirection of the fastening dome. In a particularly preferred manner,however, the thickening is offset in an opposite direction to adirection of rotation of the fan impeller, that is to say in thetangential direction. The fastening dome is stabilized by the thickeningso that the robustness is increased. On account of the displacement inthe opposite direction to the direction of rotation, the flow resistanceof the fastening dome to the air stream is reduced, and turbulence isconsequently further reduced. In particular, the largest extent of thefastening dome in the radial direction is offset in the oppositedirection to the direction of rotation of the fan impeller. Thelikelihood of an air stream flowing around the fastening domesubstantially in the tangential direction stalling is consequentlyfurther reduced and any flow resistance is consequently reduced further.

The end of the fastening dome that is tangential with reference to theairflow opening and is offset in the opposite direction to the directionof rotation of the fan impeller is preferably rounded. Consequently, theair stream which is set into a rotational movement during operation bymeans of the fan impeller, contacts the rounded end of the fasteningdome, insofar as the air stream additionally comprises a radialcomponent, for example as a result of centrifugal forces. Flowresistance is further reduced on account of the rounded end. As analternative to this or in combination with it, the tangential end of thefastening dome offset in the direction of rotation is also rounded. Alsooperating the fan impeller in the opposite direction to the direction ofrotation, that is to say in two directions of rotation, is consequentlymade possible, flow resistance being reduced here too. As an alternativeto this, the end is substantially tapered. On account of the end beingdesigned in such a manner, stalling after flowing around the fasteningdome is avoided, which is why the flow resistance is reduced further.

In an expedient manner, the boundary of the fastening dome is designedto be smooth in the radial direction with reference to the airflowopening, in particular the radial outer end thereof. The fastening domepreferably includes a substantially smooth surface in said portion. Thesurface is conveniently designed in a concave manner. In other words,the surface is expediently curved only in one direction. Consequently,flow resistance is further reduced and construction simplified. In aparticularly preferred manner, the cross section of the fastening domecomprises an aerodynamic profile parallel to the shroud body. In otherwords, the cross section is designed in a substantially wing-shapedmanner. Flow stalling is reliably prevented by means of such a choice.In an expedient manner, the cross section of the fastening dome isdesigned in a droplet-shaped manner parallel to the shroud body.Consequently, the fastening dome comprises a comparatively smallc_(w)-value, and flow resistance is further reduced.

For example, the fastening dome is designed as a solid part. In aparticularly preferred manner, the fastening dome is, however, hollow.In this connection, the fastening dome comprises an opening whichextends, in particular, perpendicularly to the airflow opening, that isto say in the axial direction. The opening is expediently designed in ablind-hole-like manner and/or is closed on one side by means of theshroud body. On account of such a design, the weight of the fasteningdome is reduced so that mounting is simplified. The costs of materialsare also reduced. In addition, producing a comparatively large fasteningdome, that is to say, in particular one with a comparatively largeperiphery, is also made possible in this way, which increasesrobustness. On account of the opening, it is also possible to producethe fastening dome with a constant wall thickness and/or with a wallthickness which does not exceed a certain value, for example 0.5 cm.Consequently, production in a plastics material injection moldingprocess is also possible, deformation being able to be substantiallyexcluded. Thus, a thickness of the wall of the fastening dome is limitedon account of the airflow opening, which is why the fastening dome canbe created in a normal process using a plastics material injectionmolding method, comparatively low production tolerances being able to bechosen.

The fan shroud preferably includes an edge which is attached to theshroud body, preferably integrally molded on and in a particularlypreferred manner in one piece with said shroud body. In an expedientmanner, the edge surrounds the airflow opening on the circumferentialside. The airflow opening is consequently delimited conveniently bymeans of the edge. The edge is in particular designed in a substantiallyhollow cylindrical manner and comprises, for example, an extent ofbetween 0.01 m and 0.05 cm perpendicularly to the shroud body, that isto say in the axial direction. The air stream is conducted through theairflow opening comparatively effectively during operation by means ofthe edge. The edge also ensures that the air stream actually passes thefan impeller and formation of leakage air is reduced. The edge isconveniently arranged concentrically with respect to the airflow openingand/or to the possible fan impeller. The edge expediently merges intothe fastening dome. Consequently, the fastening dome and the edge aremutually stabilized, which increases the robustness of the fan shroud.Installation space is also reduced in this way. The edge expedientlyforms the radially inner end of the fastening dome at least in part.

The strut comprises, for example, at least in part, a radial progressionwith reference to the airflow opening. In a particularly preferredmanner, however, the strut is arranged strictly radially andconsequently lies in a plane which is perpendicular to the extent of theairflow opening and reaches through the mid-point of the airflowopening. Consequently, the strut comprises a comparatively short length,which is why its weight is reduced. The rigidity of the strut is alsoincreased in this way so that the robustness of the fan shroud isincreased. In this connection, the strut has its largest extent, forexample, in the radial direction. In particular, the extent in saiddirection is greater than two times, four times or ten times the extentin the other direction.

In a particularly preferred manner, the strut is inclined with referenceto the shroud body. Consequently, the strut comprises at least onecomponent in the axial direction and/or tangential direction when theextent of the strut in said directions is also reduced expedientlycompared to the radial extent. Consequently, the strut encloses an anglewith reference to the shroud body and consequently also with referenceto the fastening dome. In particular, the angle is between 30° and 75°.For example, the angle is between 40° and 50°. On account of theinclination, the air stream which passes through the airflow opening isadditionally conducted by means of the strut, and the strut comprises asmaller flow resistance. The strut preferably comprises a profile, inparticular perpendicularly to the progression thereof. In a particularlypreferred manner, the profile is an aerodynamic profile and/or isdesigned in a droplet-shaped manner. Consequently, flow resistance isfurther reduced and formation of turbulent flows avoided. As aconsequence, efficiency is further increased. The inclination of thestrut is preferably dependent on the individual application and on theamount of air to be conveyed.

The fan shroud preferably includes further struts and further fasteningdomes. In this connection, all struts and fastening domes serve forattaching the motor mount to the shroud body. In this case, all strutsare attached to the motor mount, expediently to the ends thereof. Thereare preferably the same number of fastening domes as struts, and theyare consequently suitably assigned to one another. All fastening domesand/or struts are preferably designed so as to be structurally identicalto one another, which simplifies production. In particular, the strutsand/or fastening domes are arranged in a rotationally symmetrical mannerwith reference to the mid-point of the airflow opening. For example, thefan shroud comprises between two and fourteen such struts or fasteningdomes. Consequently, the fan shroud preferably includes a total ofbetween three and fifteen such struts or fastening domes.

The cooler fan is a component part of a motor vehicle and servesexpediently for cooling an internal combustion engine. In other words,the cooler fan is a main fan. As an alternative to this, the cooler fanis, for example, a component part of an air conditioning system or of anauxiliary unit of the motor vehicle. The cooler fan includes a coolerwhich comprises in particular a cooler network, through which a numberof pipes are preferably conducted. The cooler network, in thisconnection, is expediently in thermal contact with the pipes. In apreferred manner, a coolant is conducted inside the pipes in operation.The cooler network is designed, for example, in a substantially cuboidmanner. In addition, the cooler fan includes a fan shroud with a shroudbody which comprises a round airflow opening for a fan impeller. Inaddition, the fan shroud includes a motor mount which is arranged abovethe airflow opening and is attached to a fastening dome by means of astrut, expediently by means of multiple struts. The fastening dome isattached to the shroud body and is oriented perpendicularly to saidshroud body. The radially outer end of the fastening dome with referenceto the airflow opening is at a varying distance from the mid-point ofthe airflow opening.

The fan shroud is attached, expediently fastened, to the cooler. Forexample, the fan shroud is screw-connected to the cooler or is bonded tosaid cooler. In particular, the fan shroud covers the possible coolernetwork. In other words, the fan shroud is congruent with the coolernetwork or, for example, with the complete cooler. Consequently, air isprevented from passing between the cooler and the fan shroud and the airis guided comparatively efficiently by means of the fan shroud as aresult. The fan shroud is preferably arranged downstream of the cooler,that is to say expediently behind the cooler in the direction of travelof the motor vehicle. The fastening dome, in this connection, extendsconveniently away from the cooler.

The cooler fan preferably includes an electric motor which is held bymeans of the motor mount. The electric motor is, for example, a brushcommutator motor. In a particularly preferred manner, however, theelectric motor is a brushless direct current motor (BLDC). In thisconnection, an axis of rotation of the electric motor is arrangedperpendicularly to the airflow opening and extends, in particular, alongan axial straight which reaches through the mid-point of the airflowopening. For example, the electric motor is bonded or screw-connected tothe motor mount. Consequently, the electric motor is held comparativelysecurely on the motor mount.

In addition, the cooler fan includes a fan impeller which is arranged inthe airflow opening. The fan impeller is preferably arranged parallel tothe airflow opening and lies expediently in a plane with the shroudbody. The fan impeller is driven by means of the electric motor and ispreferably attached to said electric motor, for example to a shaft ofthe electric motor. For example, the fan impeller comprises a hub whichis coupled directly with the electric motor in a mechanical manner. Anumber of fan impeller blades, which comprise, in particular, a radialand for example at least in part tangential progression, are preferablyattached to the hub. For example, the fan impeller additionally includesan outer ring, to which the fan impeller blades are attached at theradial ends thereof. The fan impeller blades are stabilized, in thisconnection, by means of the outer ring, which improves the acousticimpression. In particular, the outer ring engages in a correspondingreceiving means or contour of the shroud body, these preferably beingspaced apart from one another. A labyrinth seal is formed, inparticular, between said parts. Consequently, dispersal of leakage airis prevented. As an alternative to this or in combination with it, abrush seal or the like is arranged between the possible outer ring andthe shroud body. The edge of the fan shroud, which is attached to theshroud body, is preferably available. The outer ring is preferablysurrounded by the edge. In this connection, realization of a sealbetween said parts is simplified as a result of the edge.

The advantages and further developments named in connection with the fanshroud are also to be transferred analogously to the cooler fan and viceversa.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment is explained in more detail below by way of adrawing, in which:

FIG. 1 shows a schematic representation of a land-based motor vehiclewith a cooler fan;

FIG. 2 shows a simplified schematic representation of an explodeddrawing of the cooler fan in part with a fan shroud; and

FIG. 3 shows a perspective representation of a detail of the fan shroud.

Parts which correspond to one another are provided with the samereference symbols in all the figures.

DETAILED DESCRIPTION

As required, detailed embodiments of the present disclosure aredisclosed herein; however, it is to be understood that the disclosedembodiments are merely exemplary of the disclosure that may be embodiedin various and alternative forms. The figures are not necessarily toscale; some features may be exaggerated or minimized to show details ofparticular components. Therefore, specific structural and functionaldetails disclosed herein are not to be interpreted as limiting, butmerely as a representative basis for teaching one skilled in the art tovariously employ the present disclosure.

FIG. 1 shows a simplified schematic representation of a motor vehicle 2with an internal combustion engine 4. The motor vehicle 2 is driven bymeans of the internal combustion engine 4. For this purpose, theinternal combustion engine 4 is operatively connected to at least one ofthe four wheels 6 of the motor vehicle 2 by means of a drive train whichis not shown in any more detail. In addition, the motor vehicle 2includes a cooler fan 8 which serves for cooling the internal combustionengine 4. Consequently, the cooler fan 8 is a main fan of the motorvehicle 2. The cooler fan 8 is connected to the internal combustionengine 4 in a fluid-technical manner by means of a number of lines 10,through which a coolant is conducted during operation from the coolerfan 8 to the internal combustion engine 4 and there through coolingchannels. Excessive heat is absorbed by means of the coolant and runback to the cooler fan 8, by means of which the coolant is cooled.

The cooler fan 8 comprises a heat exchanger or cooler 12 with a coolernetwork which is not shown in any more detail, through which coolernetwork a number of pipes are run and are in thermal contact therewith.The pipes are coupled in a fluid-technical manner with the lines 10 sothat, in operation, the coolant is conducted through the pipes. Thecooler fan 8 additionally includes a fan shroud 14 which is arrangeddownstream of the cooler 12 in a direction of travel 16 of the motorvehicle 2. An electric motor 18 is fastened to the fan shroud 14. Inoperation, airflow passes through the cooler 12 and is formed suitablyby means of the fan shroud 14. When the motor vehicle 2 stands still,air is sucked through the cooler 12 by means of the electric motor 8 sothat, in operation, the cooler 12 is traversed substantially always bythe air stream or at least in dependence on existing requirements. Thecooler 12 is consequently cooled, which is why the cooler fan 8 does notoverheat even after the internal combustion engine 4 has been operatingfor a comparatively long time. In addition, the air passing through thecooler fan 8 is conducted to the internal combustion engine 4 by meansof the fan shroud 14 and said internal combustion engine is additionallycooled from outside in this way.

FIG. 2 shows a simplified schematic representation in perspective of anexploded drawing of the cooler fan 8, the cooler 12 being omitted. Thefan shroud 14 is fastened to the cooler 12 and fully covers the coolernetwork, which is not shown in any more detail, and is congruent withthe same. The fan shroud 14 includes a shroud body 20 which is designedin a substantially flat manner. The shroud body 20 comprises a roundairflow opening 22 which, just as the shroud body 20, is orientedperpendicularly to the direction of travel 16. The airflow opening 22comprises a diameter of 30 cm and is surrounded circumferentially by anedge 24 which is designed in a hollow cylindrical manner and is arrangedconcentrically to the airflow opening 22. The diameter of the edge 24 isequal to the diameter of the airflow opening 22, and the edge 24comprises a length of 2 cm in the axial direction with reference to theairflow opening 22, that is to say parallel to the direction of travel16. In the mounted state, the edge 24 is situated on the side of theshroud body 20 remote from the cooler 12.

The fan shroud 14 additionally includes a total of four structurallyidentical protrusions or fastening domes 26 which are arranged in arotationally symmetrical manner with reference to the airflow opening22. In this connection, the edge 24 merges into the fastening dome 26,the radially inner surfaces or inner ends 28 thereof also being at adistance of 15 cm from the mid-point. The radially inner ends 28 aredefined, in this case, with reference to the airflow opening 22 and themid-point thereof. The fastening domes 26 extend with reference to theairflow 22, that is to say in the opposite direction to the direction oftravel 16, away from the cooler 12. The fastening domes 26 areconsequently oriented perpendicularly to the shroud body 20 and extendsubstantially in the opposite direction to the direction of travel 16.In each case, a strut 30 is integrally molded on and consequentlyattached to each of the fastening domes 26, said struts each comprisinga radial progression and being structurally identical to one another. Inthis connection, the struts 30 are at a distance from the shroud body 20in the axial direction, that is to say parallel to the direction oftravel 16. A motor mount 32, which is consequently arranged above theairflow opening 22 and is positioned concentrically to said airflowopening, is attached to the remaining free ends of the beam-shapedstruts 30. The motor mount 32 is ring-shaped and comprises a diameter of10 cm. The motor mount 32, the struts 30, the fastening domes 26, theedge 24 and the shroud body 20 are produced in one piece together in aplastics material injection molding process, for example from apolyamide (PA).

In the mounted state, the electric motor 18 is held by the motor mount32, and the electric motor 18 is consequently fastened to said motormount. In this connection, the electric motor 18 is situated on the sideof the fan shroud 14 located opposite the cooler 12. A shaft 34 of theelectric motor 18 projects through the motor mount 32 in the directionof travel 16 and is non-rotatably fastened to a hub 36 of a fan impeller38. The fan impeller 38 is consequently driven by means of the electricmotor 18 which is held by means of the motor mount 32. A number of fanimpeller blades 40, which are surrounded circumferentially by means ofan outer ring 42 and are attached to said outer ring, are attached tothe hub 36. The hub 36, the fan impeller blades 40 and the outer ring 42are created in one piece in a plastics material injection moldingprocess.

In the mounted state, the fan impeller 38 is arranged inside the airflowopening 22 parallel to said airflow opening, the outer ring 42 beingsurrounded radially in a circumferential manner by means of the edge 24.In operation, the fan impeller 38 is rotated by means of the electricmotor 18 and air is consequently sucked through the airflow opening 22in the opposite direction to the direction of travel 16. In this case, amovement component in the axial direction, that is to say in theopposite direction to the direction of travel 16 and in the radialdirection with reference to the airflow opening 22, is introduced intothe air stream on account of the rotational movement. Air is preventedfrom flowing through between the outer ring 42 and the edge 24 onaccount of a seal, not shown in any more detail, for example a labyrinthseal.

In addition, the fan shroud 14 includes a dynamic pressure control valve44 which includes an opening which is covered by means of a valve 46. Ifa comparatively high (air) pressure prevails in the direction of travel16 upstream of the fan shroud 14, in particular in the case of the motorvehicle 2 moving in a comparatively quick manner, the air is obstructedin part from passing through the airflow opening 22 on account of thefan impeller 38 or the fan impeller 38 would have to be rotatedcomparatively quickly. However, this would result in increased load onthe electric motor 18 and on the further components and in an increasednoise development. The valve 46 is consequently pivoted from a certainpressure and the opening released so that air is able to flow throughsaid valve. Consequently, the throughput of air through the cooler 12,which is situated upstream of the fan shroud 14 in the direction oftravel 16, is increased. In the case of comparatively low air pressureupstream of the fan shroud 14, as is the case when the motor vehicle 2is at a standstill, the valve 46 is closed so that the forming of acircular air stream which just passes through the opening of the dynamicpressure control valve 46 and the airflow opening 22 is prevented.Consequently, the cooler 12 is also always traversed by a sufficient airstream.

FIG. 3 shows a perspective representation of a detail of the fan shroud14, the airflow opening 22 only being shown in part. The fan impeller38, which includes the pot-shaped hub 36, the opening of which isoriented in the opposite direction to the direction of travel 16, ispositioned in the airflow opening 22. In the mounted state, the electricmotor 18, by means of which the fan impeller 38 is rotated in adirection of rotation 48, lies at least in part inside the hub 36. Inthis connection, the fan impeller blades 40, which are surrounded by theouter ring 42, are suitably formed.

The edge 24 merges into the radially inner end 28 of the only shownfastening dome 26 which is consequently designed in smooth manner. Thefastening dome 26 comprises a droplet-shaped cross sectionperpendicularly to the axial direction, that is to say perpendicularlyto the direction of travel 16 and parallel to the shroud body 20. As aconsequence, the radially outer surface or outer end 50 of the fasteningdome 26, which is defined with reference to the airflow opening 22, isat a varying distance from the mid-point of the airflow opening 22.Consequently, the fastening dome 26, on account of the constant distancebetween the radially inner end 28 and the mid-point of the airflowopening 22, comprises a thickening 52. The thickening 52 is offset inthe opposite direction to the direction of rotation 48 of the fanimpeller 38, and the tangential end 54 of the fastening dome 26 situatedthere is rounded. In other words, the position of the end 54 is definedwith reference to the airflow opening 22. The opposite end 56, that isto say the tangential end 56 of the fastening dome 26 offset in thedirection of rotation 48 of the fan impeller 38, is tapered so that thedroplet shape is formed. Consequently, the fastening dome 26 of thedroplet-shaped cross section comprises an aerodynamic profile.

In operation, air is sucked through the airflow opening 22 counter tothe direction of travel 16 by means of the fan impeller 38, said aircomprising an axial movement component with reference to the airflowopening 22. On account of the rotational movement of the fan impeller38, the air is additionally set in rotation and consequently comprises atangential movement component (swirl). On account of the centrifugalforces occurring in this case, the air is additionally moved outward inthe radial direction with reference to the airflow opening 22. There itcontacts the fastening domes 26, the air initially contacting therounded end 54. On account of the aerodynamic profile, a substantiallylaminar flow is realized, and the air stream is prevented from stallingat the fastening dome 26, even if the air stream is conducted to theinternal combustion engine. Efficiency is consequently increased, and arequired output to drive the fan impeller 38 is reduced. Noisedevelopment is also reduced.

The struts 30 are additionally inclined with reference to the shroudbody 20 and consequently, also with reference to the direction of travel16, enclose an angle which deviates from 90°. In particular, the angleis between 40° and 50°. Consequently, the air is conducted additionallyby means of the struts 30, and an effective cross sectional area for theair stream is reduced. In particular, the strut 30 also comprises anaerodynamic profile as cross section in the radial direction withreference to the airflow opening 22, which further reduces a formationof turbulence.

The fastening dome 26 is designed in a hollow manner and comprises anopening 58, which extends in the axial direction, that is to sayparallel to the direction of travel 16, and is designed in the manner ofa blind hole. The weight is reduced on account of the opening 58. Amaximum thickness of the plastics material is also reduced in this wayso that comparatively simple production is made possible withoutanticipating the fastening dome 26 being deformed when the plasticsmaterial hardens and/or when it is removed from a mold.

In summary, the attachment of the struts 30 to the shroud body 20,namely the fastening domes 26, in the axial direction, that is to sayparallel to the direction of travel 16, is designed as a strung flowprofile, the inflow side of which is in the opposite direction to thedirection of rotation of the fan, that is to say the direction ofrotation 48. In other words, the end 54 of the fastening dome 26, whichis tangential with reference to the airflow opening 22 and is offset inthe opposite direction to the direction of rotation 48 of the fanimpeller 38, is rounded, and the fastening dome 26 comprises thethickening 52 which is offset in the opposite direction to the directionof rotation 48 of the fan impeller 38. Consequently, lower flowresistance is realized for the air emerging with circumferentialcomponents. Less flow separation also occurs in said region, that is tosay fewer stalls.

For example, the cross section of the fastening dome 26 is constant orit is reduced in the opposite direction to the direction of travel 16 asthe distance from the shroud body 20 increases. In other words, thefastening dome 26 is scaled and designed with a bevel. As an alternativeto this or in combination with it, the fastening dome 26 is a hollowbody and is consequently hollow. In this way, production is possible, inparticular, with a one-sided core in the injection molding process. Inparticular, the injection molding mold comprises just one one-sidedcore. Consequently, openings can be omitted in the mold in the regionbetween the shroud body 20 and the airflow opening 22. It is alsopossible to influence the rigidity in dependence on the profile designof the fastening dome 26.

The disclosure is not limited to the exemplary embodiment describedabove. On the contrary, other variants of the disclosure can also bederived here from by the expert without departing from the object of thedisclosure. In addition, in particular, all the individual featuresdescribed in connection with the exemplary embodiment are able to becombined together in another manner without departing from the object ofthe disclosure.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the disclosure. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the disclosure.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the disclosure.

LIST OF REFERENCES

-   2 Motor vehicle-   4 Internal combustion engine-   6 Wheel-   8 Cooler fan-   10 Line-   12 Cooler-   14 Fan shroud-   16 Direction of travel-   18 Electric motor-   20 Shroud body-   22 Airflow opening-   24 Edge-   26 Fastening dome-   28 Radially inner end-   30 Strut-   32 Motor mount-   34 Shaft-   36 Hub-   38 Fan impeller-   40 Fan impeller blade-   42 Outer ring-   44 Dynamic pressure control valve-   46 Valve-   48 Direction of rotation-   50 Radially outer end-   52 Thickening-   54 End-   56 End-   58 Opening

What is claimed is:
 1. A fan shroud of a motor vehicle comprising: ashroud body defining a round airflow opening for a fan impeller andincluding a motor mount arranged above the airflow opening and attachedby a strut to a fastening dome, wherein the fastening dome is attachedto the shroud body and is oriented at least in part perpendicularly tosaid shroud body, and wherein a radially outer end of the fastening domeis at a varying distance from a mid-point of the airflow opening.
 2. Thefan shroud of claim 1, wherein the radially inner end of the fasteningdome is at a constant distance from the mid-point of the airflowopening.
 3. The fan shroud of claim 1, wherein the fastening domecomprises a thickening which is offset in an opposite direction to adirection of rotation of the fan impeller.
 4. The fan shroud of claim 1,wherein the fastening dome includes an end that is tangential withreference to the airflow opening and is offset in the opposite directionto the direction of rotation of the fan impeller, wherein the end of thefastening dome is rounded.
 5. The fan shroud of claim 1, wherein thefastening dome includes a cross-section that is parallel to the shroudbody and is droplet-shaped.
 6. The fan shroud of claims 1, wherein thefastening dome is hollow.
 7. The fan shroud of claim 1 furthercomprising an edge surrounding the airflow opening circumferentially andmerging into the fastening dome, wherein the edge is attached to theshroud body.
 8. The fan shroud of claim 1, wherein the strut extendsradially with reference to the airflow opening.
 9. The fan shroud ofclaim 1, wherein the strut is inclined with reference to the shroudbody.
 10. The fan shroud of claim 1, wherein the fan shroud includesbetween two and fourteen structurally identical struts and between twoand fourteen structurally identical fastening domes.
 11. A cooler systemof a motor vehicle comprising: a fan; a cooler; and a fan shroudaccording to claim 1, wherein the fan shroud is attached to the cooler.12. The cooler system of a motor vehicle of claim 11, wherein the fan isarranged in the airflow opening, and wherein the cooler system furthercomprises an electric motor secured to the motor mount, wherein theelectric motor is configured to drive the fan.
 13. A cooling system fora motor vehicle comprising: a heat exchanger; a fan configured to directair across the heat exchanger; and a fan shroud secured to the heatexchanger, the fan shroud, having a shroud body, defining an openingreceiving the fan such that the fan rotates about an axis, having atleast one protrusion disposed radially outward of the opening andextending axially from the shroud body relative to the axis, each of theat least one protrusions having an outer surface that faces radiallyoutward relative to the opening, wherein a distance between each of theouter surfaces a mid-point of the opening varies, and having a motormount which is disposed over the opening and is secured to the shroudbody via at least one strut, each of the at least one struts extendingbetween the motor mount and one of the at least one protrusions.
 14. Thecooling system of claim 13 further comprising an electric motor securedto the motor mount, wherein the electric motor configured to drive thefan.
 15. The cooling system of claim 13, wherein the at least oneprotrusions are perpendicular to the shroud body.
 16. The cooling systemof claim 13, wherein each of the at least one protrusions have an innersurface that faces radially inward relative to the opening, and whereina distance between each of the inner surfaces and the mid-point of theopening is constant.
 17. The cooling system of claim 13, wherein each ofthe at least one protrusions have a thickness that increases in anopposite direction to a direction of rotation of the fan.
 18. Thecooling system of claim 13, wherein a cross-section of each of the atleast one protrusions that is parallel to the shroud body isdroplet-shaped.
 19. The cooling system of claim 13, wherein an edge ofthe shroud body circumferentially surrounds the opening and merges intothe at least one protrusion.
 20. The cooling system of claim 13, whereineach of the at least one struts is inclined with respect to the shroudbody at an angle that ranges between 30° and 75°.